Exercise physiology

Question 1

What are the changes to an ECG graph during exercise?

Answer 1

Shortening of the Q-T interval
Shortening of R-R interval
Slight increase in P wave amplitude
Shift to the right of QRS axis
Small S-T segment depresion
Decreased T-wave amplitude

Question 2

What is the equation for RQ value?

Answer 2

RQ = volume of CO2 expired/Volume of O2 inhaled

Question 3

What can the RQ value tell you about the metabolites being used?

Answer 3

Close to 1 = glucose

Close to 0.7 = free fatty acids

Question 4

What happens to systolic and diastolic blood pressure during exercise and why?

Answer 4

Systolic pressure increases as cardiac output increases due to greater stroke volume and heart rate.
Diastolic pressure remains constant or decreases slightly as vasoacitve metabolites being produced by heavy exercise cause vasodilation of blood vessels.

Question 5

Describe the changes in blood flow during exercise

Answer 5

Cardiac output is 5 times greater. Most of the blood goes to the muscles. Much less blood is going to the digestive system and the kidneys.

Question 6

What are the mechanisms controlling heart rate and blood pressure during exercise?

Answer 6

Baroreceptors: Located in aortic arch and carotid artery. When they detect stretch they cause a decrease in blood pressure.
Vagus nerve: To reduce heart rate the vagal inhibition acts through the parasympathetic system
Sympathetic: Nor-adrenaline and adrenaline act on GPCR’s to cause contraction of the heart and increase heart rate
Vessels: Blood pressure is influenced by the diameter and resistance of blood vessels
Dilation caused by vasoactive metabolites
Endothelial regulation through release of NO